Floating cover system for large open containers

ABSTRACT

A floating cover system for a container with an open top includes a plurality of floating cover sections with cover connector devices spaced along a periphery of each at a connector spacing. A ballast tube has tube connector devices spaced along the exterior thereof at the same connector spacing. The ballast tube is open at each end and longer ballast tubes also define access holes along a length thereof. Water enters an interior of the ballast tube through the open ends thereof and the access holes, if any. When all the cover sections are installed in the container, the open top of the container is substantially covered by cover sections joined together at seams where adjacent cover connector devices are connected together, and the tube connectors are connected to the cover connectors along a ballast seam such that the ballast tube is located under the ballast seam.

This invention is in the field of liquid storage and in particular large liquid tanks, containers, reservoirs and the like with open tops containing liquid such as are used for heating large quantities of water for formation fracturing in the petroleum recovery and like industries, and also for storing large quantities of water in dry climates where evaporation is problematic.

BACKGROUND

In some mining, industrial, and agricultural applications, very large quantities of liquid are required to be stored. For example in petroleum oil and gas recovery operations, it is common practice to fracture an underground formation by injecting liquid at high pressure into the formation. Fracturing operations, commonly called fracking, can require very large amounts of heated liquid, which must be stored and heated in a temporary container typically a tank or pit set up at the work site. Some of the these tanks can be twelve to fourteen feet high, and 150 or more feet across, and contain two million gallons of liquid.

Frack tanks are transported to the work site where they are set up and filled with liquid that typically must be heated to a desired temperature for use in the fracking operation. Because of their large size, it is not practical to close the tops of the tanks and so they are open, such that very significant heat loss occurs from the large exposed top surface of the water as it is being heated. Also in hot summer temperatures a significant amount of water can be lost to evaporation.

The liquid used in fracking operations is water mixed with a variety of chemicals. Once erected, the frack tank is filled by hauling or pumping water from a river or the like, and this filling operation can take three to four days. The water is heated during and/or after filling by large mobile heating units, and once heated the water is used within a day or so, unless there are operational delays, which may result in needing to reheat the water. With the significant heat losses from the open water surface, it may be required to add heat constantly to maintain a satisfactory temperature during use. The large mobile heating units are costly and in demand so rentals costs are high and it is sometimes difficult to schedule the filling of the tanks to coordinate with the arrival of the heating units. The heating operation is therefore costly.

To reduce heat loss and evaporation these tanks can be covered with a flexible membrane however wind often makes this process problematic. Canadian Patent Application Number 2836954 of Bleile et al. discloses a system for securing such membrane covers.

Floating insulated tank covers are also known. Canadian Patent Application Number 2,832,802 of Hindbo discloses a cover for large frack tanks comprising a plurality of inflatable bladders that are shaped generally like pie slices, and tied together. The bladders are also connected by an air channel such that pressurized air can be continuously pumped into each of the bladders to keep them inflated.

Other floating tank covers are disclosed for example in U.S. Pat. No. 7,240,804 to King et al., U.S. Pat. No. 6,922,956 to Johnson, et al., and U.S. Pat. No. 5,704,509 to Rosenkrantz.

In other industries, containers, reservoirs or open pits are covered in dry climates to preserve water and substantially reduce evaporation losses when it is used for livestock or industrial uses.

SUMMARY OF THE INVENTION

The present disclosure provides a floating cover system for tanks, open pits, or like containers that overcomes problems in the prior art.

The present disclosure provides a floating cover system for a container with an open top. The system comprises a plurality of cover sections, each cover section adapted to float on a water surface, and a plurality of cover connector devices attached to, and equally spaced along, a periphery of each cover section at a connector spacing. A ballast tube has a plurality of tube connector devices attached to, and equally spaced along, a length of an exterior of the ballast tube at the same connector spacing. The ballast tube is open at each end thereof such that water enters an interior of the ballast tube through the open ends thereof. The cover sections are configured such that when all the cover sections are installed in the container, the open top of the container is substantially covered by cover sections joined together at seams where adjacent cover connector devices are connected together, and the tube connectors are connected to the cover connectors along a ballast seam such that the ballast tube is located under the ballast seam.

The presently disclosed floating cover system is highly resistant to wind forces which can be significant depending on the location of the container. The system is also convenient to transport and can be readily installed on the floor of an empty container, or can be installed on a filled container if. The system is also readily transportable and adaptable to different sizes of containers.

DESCRIPTION OF THE DRAWINGS

While the invention is claimed in the concluding portions hereof, preferred embodiments are provided in the accompanying detailed description which may be best understood in conjunction with the accompanying diagrams where like parts in each of the several diagrams are labeled with like numbers, and where:

FIG. 1 is a schematic top view of an embodiment of a floating cover system of the present disclosure installed in a container with an open top;

FIG. 2 is a schematic sectional side view along line 2-2 in FIG. 1;

FIG. 3 is a schematic top view of a rectangular cover section attached to an edge cover section in the embodiment of FIG. 1;

FIG. 4 is a perspective end view of the open end of a ballast tube of the embodiment of FIG. 1;

FIG. 5 is a schematic top view of the fabric strip, connector rings and weight member attached along a periphery of a cover section;

FIG. 5A is a schematic end view of the connector rings of one cover section attached to the connector rings of an adjacent cover section in the embodiment of FIG. 1, with the fabric strips weighted down into the water by a cable, chain, or the like;

FIG. 6 is a schematic top view of the embodiment of FIG. 1 installed in a container with a smaller diameter than the container of FIG. 1;

FIG. 7 is a schematic top view of the embodiment of FIG. 1 installed in a container with a smaller diameter than the container of FIG. 6;

FIG. 8 is a schematic end view of an inflatable cover section of the embodiment of FIG. 1 showing the attachment of the ballast tube;

FIG. 9 is a schematic sectional view along line 9-9 in FIG. 8;

FIG. 10 is a schematic sectional view of the resilient air tight section tubes and fabric shell of the inflatable cover section of FIG. 8;

FIG. 11 is a schematic sectional view showing the construction of a cover section made from a floating sheet material covered by a fabric material; and

FIG. 12 is a schematic side sectional view of a cover sheet comprising a flexible bubble sheet with air bubbles defined on the bottom surface thereof.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

FIGS. 1 and 2 schematically illustrate an embodiment of a floating cover system 1 of the present disclosure installed in a container 3 with an open top 5. The system 1 comprises a plurality of cover sections 7, each cover section 7 adapted to float on a water surface. Cover connector devices 9 are attached to, and equally spaced along, a periphery of each cover section 7 at a connector spacing CS, as shown in FIG. 3.

A ballast tube 11, as shown in FIG. 4, has a plurality of tube connector devices 13 attached to, and equally spaced along, a length of an exterior of the ballast tube 11 at the connector spacing CS. The ballast tube 11 is open at each end thereof such that water enters an interior of the ballast tube 11 through the open ends 17 thereof longer ballast tubes 11 further define a plurality of access holes 15 spaced along a length thereof such that water enters the interior of the ballast tube 11 through the open ends 17 thereof and the access holes 15. In these longer tubes as well, the access holes 15 allow air to be pushed out of the ballast tube 11 by water flowing into the ballast tube 11 from each open end.

The cover sections 7 are configured such that when all the cover sections 7 are installed in the container 3, the open top 5 of the container 3 is substantially covered by cover sections 7 joined together at seams 19 where adjacent cover connector devices 9 are connected together, and the tube connectors 13 are connected to the cover connectors 9 along a ballast seam 19A such that the ballast tube 11 is located under the ballast seam 19A.

The ballast tubes 11 fill with water and anchor the cover sections 7 along the ballast seams 19A. As shown in FIG. 1, the ballast seams 19A, with the ballast tubes 11 suspended below them, are placed at locations that are selected depending on the strength of winds expected, the direction of the prevailing winds, and like considerations.

The cover connector devices are conveniently provided by connector rings 21 as schematically illustrated in FIGS. 5 and 5A. Conveniently the connector rings 21 are attached to a fabric strip 23 and the fabric strip 23 is attached along the periphery of each cover section 7. Adjacent connector rings 21 on adjacent cover sections 7 are connected together by a tie member, such as a carabiner 25 or like metal loop with a spring-loaded gate.

To reduce the occurrence of wind entering under the edges of the cover sections 7 an inner edge 23A of each fabric strip 23 is attached along the periphery of the corresponding cover section 7, and the connector rings 21 are attached in proximity to the inner edges 23A of the fabric strips 23 such that the fabric strips 23 extend outward from the connector rings 21. Conveniently the connector rings 21 are attached to a fabric tape 23C which can be readily sewn onto the fabric strips 23. When placed in the water the outer edges 23B of the fabric strips 23 hang down in the water where the wind cannot get under them. A weight member 23D, such as a chain, cable, weighted rope, or the like, can be attached along the outer edge 23B of the fabric strips 23 to ensure same sink into the water.

Conveniently the system comprises a plurality of rectangular cover sections 7A with the same dimensions, and wherein each rectangular cover section 7A has a width dimension W and a length dimension L substantially equal to twice the width dimension W. The fabric strip 23 is attached along each edge of each rectangular cover section 7A such that a connector ring 21 is located at each corner 27 of each rectangular cover section 7A, and the connector spacing CS is an even multiple of the width dimension W. It is contemplated for example that a rectangular cover section 7A with a width dimension of 18 feet, a length dimension of 36 feet, and a connector spacing of three feet will allow for convenient covering of a variety of tank sizes. Other dimensions can be used depending on circumstances.

The container 3 comprises a substantially cylindrical wall 29 and the open top 5 is circular. The cover sections 7 include a plurality of rectangular cover sections 7A, and a plurality of edge cover sections 7B that are configured to substantially cover edge areas of the open top 5 between the rectangular cover sections 7A and the cylindrical wall 29 when the cover sections 7 are installed. The cover sections 7 are also configured such that when all the cover sections 7 are installed as shown in FIG. 1, a small space 31 is formed between the cover sections 7 and the wall 29 such that the cover sections 7 not tight against the wall 29 and so are able to move up and down as a level of water 33 in the container 3 moves up and down.

FIGS. 1 and 2 schematically illustrate the system 1 in use on a first container 3 with a circular top 5 with a first diameter D1. FIG. 6 schematically illustrates the system 1 in use on a second container 3′ with a circular top 5′ with a second diameter D2 smaller than the first diameter D1. The system 1 thus comprises a plurality of rectangular sections 7A with the same dimensions as illustrated in FIG. 3, a plurality of first edge cover sections 7B configured to substantially cover edge areas of the open top 5 between the rectangular cover sections 7A and the cylindrical wall 29 when the cover sections 7 are installed in the first container 3, and a plurality of second edge cover sections 7C configured to substantially cover edge areas of the open top 5′ between the rectangular cover sections 7A and the cylindrical wall 29′ when the cover sections 7 are installed in the second container 3′.

FIG. 7 schematically illustrated a third container 3″ with a circular top 5″ with a third diameter D3 smaller than the second diameter D2. Here the system includes a plurality of third edge cover sections 7D configured to substantially cover edge areas of the open top 5″ between the rectangular cover sections 7A and the cylindrical wall 29″ when the cover sections 7 are installed in the third container 3″. It can be seen that by using a standard rectangular sheet section 7A, virtually any diameter container can be covered by providing edge cover sections configured for a particular size open top.

As seen in FIG. 4, the tube connector devices 13 are provided by a flap 35 extending from the ballast tube 11 and a connector hole 37 defined in the flap 35. As can be seen in FIG. 8 the connector holes 37 are aligned with the cover connector devices 9, such as rings 21, attached along each cover section 7 at the same connector spacing, such that the tie member passes through the connector holes connected to adjacent connector rings 21 along the ballast seams 19A by the carabiner 25. Conveniently the flap 35 is continuous along the exterior length of the ballast tube 11 and the holes 37 are spaced along the flap 35 at the connector spacing CS.

The ballast tube 11 could be made of a rigid material however to facilitate transport the ballast tube 11 is conveniently formed from a flexible fabric material with a stiff ring 39 attached at each open end 17 thereof. The stiff ring 39 holds the fabric material open such that water flows into each open end 17 of the ballast tube 11. When filled with water the ballast tube 11 resists upward movement of the attached cover sections 7 and prevents them from blowing away.

FIGS. 8-10 illustrate cover sections 7 that are inflatable. Each cover section 7 comprises a plurality of flexible and resilient air tight section tubes 41, as seen in FIG. 9, each defining a closable air filling orifice 43. The sections tubes 41 are joined together to form each cover section 7 by a fabric shell 45 comprising an upper sheet of fabric shell material 45A and a lower sheet of fabric shell material 45B that holds the tubes 41 together and also defines the diameter of the tubes 41 which will stretch when inflated. The upper and lower sheets of fabric shell material 45A, 45B are joined together between adjacent section tubes 41, as shown in FIG. 10, s by sewing, adhesives, or the like. The cover sections 7 can conveniently be deflated and folded for transport at one work site, then unfolded and inflated at the next work site. Inflation pressures are low, simply enough to maintain the shape of the caver sections 7.

FIG. 11 schematically illustrates a cover section 7′ comprising a sheet of flexible foam material 47 encased in a fabric material 49 with connector rings 21 attached to the periphery thereof. The flexible foam and fabric cover allows the cover sections to be rolled into a compact shape for transport.

The cover sheets can also be provided by flexible bubble sheets 51 with air bubbles 53 defined on the bottom surface 51A thereof as schematically illustrated in FIG. 12. The bubbles 53 provide an enlarged surface area in contact with the water surface when the bottom surface of the sheet 51 is laid on the water surface. It is contemplated that this will increase the resistance of the bubble sheets 51 to lifting off the water surface.

The inflatable cover sections 7 and sheet material cover sections 7′ are typically only ¼ inch to one inch thick depending on the material used, with a ballast tube diameter of for example about one foot for cover sections that are 18 feet by 36 feet.

The floating cover system 1 of the present disclosure is highly resistant to wind forces which can be significant depending on the location of the container. The system 1 is convenient to transport and can be readily installed on the floor of an empty container, or can be installed on a filled container if necessary by floating the cover sections out over the water surface as they are attached, with some assistance likely required by a person floating on the surface as well. The system 1 is also readily transportable and adaptable to different sizes of containers.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous changes and modifications will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all such suitable changes or modifications in structure or operation which may be resorted to are intended to fall within the scope of the claimed invention. 

1. A floating cover system for a container with an open top, the system comprising: a plurality of cover sections, each cover section adapted to float on a water surface; a plurality of cover connector devices attached to, and equally spaced along, a periphery of each cover section at a connector spacing; a ballast tube and a plurality of tube connector devices attached to, and equally spaced along, a length of an exterior of the ballast tube at the connector spacing; wherein the ballast tube is open at each end thereof such that water enters an interior of the ballast tube through the open ends thereof; wherein the cover sections are configured such that when all the cover sections are installed in the container, the open top of the container is substantially covered by cover sections joined together at seams where adjacent cover connector devices are connected together, and the tube connectors are connected to the cover connectors along a ballast seam such that the ballast tube is located under the ballast seam.
 2. The system of claim 1 wherein the ballast tube further defines a plurality of access holes spaced along a length thereof such that water enters the interior of the ballast tube through the open ends thereof and through the access holes.
 3. The system of claim 1 wherein the cover connector devices are provided by connector rings, and wherein adjacent connector rings on adjacent cover sections are connected together by a tie member.
 4. The system of claim 3 wherein each cover section comprises a fabric strip attached along the periphery thereof, and wherein the connector rings are attached to the fabric strips.
 5. The system of claim 4 wherein an inner edge of each fabric strip is attached along the periphery of the corresponding cover section, and the connector rings are attached in proximity to the inner edges of the fabric strips such that the fabric strips extend outward from the connector rings.
 6. The system of claim 5 comprising a weight member attached along an outer edge of at least one fabric strip.
 7. The system of claim 4 comprising a plurality of rectangular cover sections with the same dimensions, and wherein each rectangular cover section has a width dimension and a length dimension substantially equal to twice the width dimension, and wherein each fabric strip is attached along each edge of each rectangular cover section such that a connector ring is located at each corner of each rectangular cover section, and wherein the connector spacing is an even multiple of the width dimension.
 8. The system of claim 7 wherein the width dimension is 18 feet, the length dimension is 36 feet, and the connector spacing is three feet.
 9. The system of claim 3 wherein the tube connector devices are provided by a flap extending from the ballast tube and a connector hole defined in the flap and wherein the connector holes are connected to adjacent connector rings by the tie member.
 10. The system of claim 9 wherein the flap is continuous along the exterior length of the ballast tube and wherein the holes are spaced along the flap at the connector spacing.
 11. The system of claim 3 wherein the tie member is provided by a carabiner.
 12. The system of claim 2 wherein the cover sections comprise a sheet of foam material.
 13. The system of claim 12 wherein the sheet of foam material is flexible and encased in a fabric material.
 14. The system of claim 2 wherein the cover sections are inflatable.
 15. The system of claim 14 wherein the each cover section comprises a plurality of flexible air tight section tubes, each section tube defining a closable air filling orifice.
 16. The system of claim 15 wherein the sections tubes are joined together to form each cover section by a fabric shell comprising an upper sheet of fabric shell material and a lower sheet of fabric shell material.
 17. The system of claim 16 wherein the upper and lower sheets of fabric shell material are joined together between adjacent section tubes.
 18. The system of claim 2 wherein the cover sections comprise a flexible sheet with bubbles formed on one side thereof, and wherein the bubbles are on a bottom surface of the cover sections such that the bubbles are in contact with the water when the cover sections float on the water surface.
 19. The system of claim 1 wherein the container comprises a substantially cylindrical wall and the open top is substantially circular, and wherein the cover sections include a plurality of rectangular cover sections, and a plurality of edge cover sections configured to substantially cover edge areas of the open top between the rectangular cover sections and the cylindrical wall when the cover sections are installed.
 20. The system of claim 19 wherein the cover sections are configured such that when the cover sections are installed, a space is formed between the cover sections and the wall such that the cover sections are movable up and down as a level of water in the container moves up and down.
 21. The system of claim 19 for use on a first container with a circular top with a first diameter and for use on a second container with a circular top with a second diameter smaller than the first diameter, the system comprising: a plurality of rectangular sections with the same dimensions, and wherein each rectangular cover section has a width dimension and a length dimension substantially equal to twice the width dimension; a plurality of first edge cover sections configured to substantially cover edge areas of the open top between the rectangular cover sections and the cylindrical wall when the cover sections are installed in the first container; a plurality of second edge cover sections configured to substantially cover edge areas of the open top between the rectangular cover sections and the cylindrical wall when the cover sections are installed in the second container.
 22. The system of claim 1 wherein the ballast tube is formed from a flexible fabric material and comprising a stiff ring attached to the ballast tube at each open end thereof, the stiff ring operative to hold the fabric material open such that water flows into each open end of the ballast tube. 